Kiddushin 3:4-5

Kiddushin 3:4

Rabbi Meir says that in order to be effective, a condition must resemble the condition used for the Tribes of Gad and Reuven. In Numbers 32:29, Moshe said, “If the tribes of Reuven and gad will pass…” and verse 32:30 says, “If they will not pass…” (i.e., one must state both alternatives). Rabbi Chananiah ben Gamliel said that it was necessary for Moshe to state both alternatives because otherwise one might have thought that these Tribes wouldn’t inherit territories in the land of Canaan either. (So both alternatives were stated in this case to clarify potential ambiguity but such is not always necessarily the case.)

Kiddushin 3:5

If a man betroths a woman thinking that she is from a kohein family and she turns out to be from a Levi family, or vice versa, or he thinks that she is poor and she turns out to be rich, or vice versa, then she is effectively betrothed because she never misled him. If a man says to a woman that she is betrothed to him after he converts, or after she converts, or after he is freed from servitude, or after she is freed from servitude, after her husband dies, or after the death of her sister (who is his wife), or after her brother-in-law performs chalitzah – in all of these cases, she is not betrothed to him. (Since he cannot betroth her in their current state, he cannot betroth her for the future until after the change in status comes about.) Similarly, if a man says to his friend, “If your wife gives birth to a daughter, she is betrothed to me,” it is ineffective. If the friend’s wife is already visibly pregnant and she gives birth to a girl, then his words are effective.